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Proceedings Paper

Turbo codes for a DWDD disc: bit length of 70nm recording with a red laser
Author(s): Shinichiro Uno; Yukinori Yamamoto; Yasuyuki Miyaoka
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Paper Abstract

Turbo codes, a partial turbo method and a serial turbo method, were experimentally applied to a Domain Wall Displacement Detection (DWDD) disk using a red laser. An effective bit length of 68nm recording was achieved by a partial turbo method with a parity bit rate of 1/17 at a bit error rate (bER) of 4x10-5 using a maximum a-posteriori probability (MAP) decoder, although a bit length of 80nm was the limit of the conventional partial response maximum-likelihood (PRML) method. It is presumable that the limit of the turbo decoding method for a DWDD disk depends on the number of consecutive 2-bit errors that occur with the disappearance of the 2T pattern. A max-log-MAP algorithm was introduced, instead of the usual MAP algorithm, to implement turbo codes in hardware, and an effective bit length of 69nm was achieved at a bER of 4x10-5.

Paper Details

Date Published: 9 September 2004
PDF: 12 pages
Proc. SPIE 5380, Optical Data Storage 2004, (9 September 2004); doi: 10.1117/12.556789
Show Author Affiliations
Shinichiro Uno, Canon Inc. (Japan)
Yukinori Yamamoto, Canon Inc. (Japan)
Yasuyuki Miyaoka, Canon Inc. (Japan)

Published in SPIE Proceedings Vol. 5380:
Optical Data Storage 2004
B. V. K. Vijaya Kumar; Hiromichi Kobori, Editor(s)

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